Dr. Barber’s lab primarily focuses on the CD4 T cell response against Mycobacterium tuberculosis (Mtb) infection. Specifically, the goals are to identify the mechanisms of CD4 T cell dependent host protection against Mtb, and understand the regulatory pathways that determine the balance between CD4 T cell dependent control of the infection and immunopathology. Much of Dr. Barber’s work has focused on the role of the inhibitory receptor, PD-1, in regulating T cell responses to chronic infections, and the lab has a major interest in understanding the mechanism through which PD-1 is required to prevent CD4 T cell driven fatal immunopathology during Mtb infection. Dr. Barber’s lab is also interested in identifying the properties of host-protective CD4 T cell response to Mtb by understanding the in vivo migratory properties, differentiation programs and effector functions of the different subpopulations of Mtb-specific Th1 cells generated after infection. Dr. Barber’s lab also has a major interest in understanding the immune mediated pathology that is associated with antiretroviral therapy of HIV infection known as Immune Reconstitution Inflammatory Syndrome (IRIS). To this end, Dr. Barber has developed a murine model of IRIS, and projects in the lab are examining the mechanisms of CD4 T cell driven pathology and factors that promote the development of IRIS when CD4 T cells reconstitute a T cell deficient host harboring a chronic infection.